But be careful to not confuse on the goal: the initial request was more that I suspect that there is a bug that prevent to disable the pull-up, and I gave current measures that show that it seems that there is a pull-up there on input even if we set to NOT use it, and that even with analog input.

pinMode(PIR_PIN, INPUT); should NOT have pull-up
pinMode(PIR_PIN, INPUT_PULLUP); uses pull-up

So, if you can measure both cases, it would be great. Many apologize if this was already your intent and I didn't catch...